MetAP2 encodes a protein that functions at least in part by enzymatically removing the amino terminal methionine residue from certain newly translated proteins, such as, glyceraldehyde-3-phosphate dehydrogenase (Warder et al. (2008) J Proteome Res 7:4807). Increased expression of the MetAP2 gene has been historically associated with various forms of cancer. Molecules inhibiting the enzymatic activity of MetAP2 have been identified and have been explored for their utility in the treatment of various tumor types (Wang et al. (2003) Cancer Res 63:7861) and infectious diseases, such as, microsporidiosis, leishmaniasis, and malaria (Zhang et al. (2002) J. Biomed Sci. 9:34). Notably, inhibition of MetAP2 activity in obese and obese-diabetic animals leads to a reduction in body weight in part by increasing the oxidation of fat and in part by reducing the consumption of food (Rupnick et al. (2002) Proc Natl Acad Sci USA 99:10730).
6-O-(4-Dimethylaminoethoxy)cinnamoyl fumagillol is a METAP2 inhibitor and is useful in the treatment of, e.g., obesity. 6-O-(4-Dimethylaminoethoxy)cinnamoyl fumagillol is characterized by formula I:

An amorphous form of a hemioxalate salt of 6-O-(4-dimethylaminoethoxy)cinnamoyl fumagillol has been prepared. However, the existence or preparation of a crystalline form of the hemioxalate salt of 6-O-(4-Dimethylaminoethoxy)cinnamoyl fumagillol does not appear to be disclosed in the art.
Polymorphism is the ability of a substance to crystallize in more than one crystal lattice arrangement. Crystallization, or polymorphism, can influence many aspects of solid state properties of a drug substance. A crystalline substance may differ considerably from an amorphous form, and different crystal modifications of a substance may differ considerably from one another in many respects including solubility, dissolution rate and/or bioavailability. Generally, it is difficult to predict whether or not a given compound will form various crystalline solid state forms. It is even more difficult to predict the physical properties of these crystalline solid state forms. Further, it can be advantageous to have a crystalline form of a therapeutic agent for certain formulations, e.g., formulations suitable for subcutaneous use.